From: Shuling Zhou <zhoushuling@xxxxxxxxxx>
After 'commit 0e6edceb8f18 ("KVM: LAPIC: Fix lapic_timer_advance_ns
parameter overflow")',a negative value can be assigned to
lapic_timer_advance_ns, when it is '-1', the kvm_create_lapic()
will judge it and turns on adaptive tuning of timer advancement.
However, when lapic_timer_advance_ns=-2, it will be assigned to
an uint variable apic->lapic_timer.timer_advance_ns, the
apic->lapic_timer.timer_advance_ns of each vCPU will become a huge
value. When a VM is started, the VM is stuck in the
"
[ 2.669717] ACPI: Core revision 20130517
[ 2.672378] ACPI: All ACPI Tables successfully acquired
[ 2.673309] ftrace: allocating 29651 entries in 116 pages
[ 2.698797] Enabling x2apic
[ 2.699431] Enabled x2apic
[ 2.700160] Switched APIC routing to physical x2apic.
[ 2.701644] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 2.702575] smpboot: CPU0: Intel(R) Xeon(R) Platinum 8378A CPU @ 3.00GHz (fam: 06, model: 6a, stepping: 06)
..........
"
'Fixes: 0e6edceb8f18 ("KVM: LAPIC: Fix lapic_timer_advance_ns
parameter overflow")'
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Signed-off-by: Shuling Zhou<zhoushuling@xxxxxxxxxx>
---
arch/x86/kvm/lapic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ebf41023be38..5feeb889ddb6 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2848,7 +2848,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
if (timer_advance_ns == -1) {
apic->lapic_timer.timer_advance_ns = LAPIC_TIMER_ADVANCE_NS_INIT;
lapic_timer_advance_dynamic = true;
- } else {
+ } else if (timer_advance_ns >= 0) {
apic->lapic_timer.timer_advance_ns = timer_advance_ns;
lapic_timer_advance_dynamic = false;
}
--
2.27.0
